• Journal of Environmental Health Sciences
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• v.44 no.2
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• pp.188-195
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• 2018

Objectives: This study aimed to investigate the association between vitamin D deficiency and the risk of diabetes mellitus, and also examined whether their association is differed by sex and age. Methods: We analyzed the data from 28,135 subjects ${\geq}20years$ old who were registered for the Korea National Health and Nutrition Examination Survey (KNHANES) 2008-2014. Vitamin D was measured using serum 25-hydroxyvitamin D (25(OH)D) concentrations. Results: After adjusting for potential confounders (age, sex, education, income, total energy intake, smoking, physical activity, body mass index, and waist circumference), lower vitamin D was dose-dependently associated with a higher risk of diabetes mellitus (p-trend=0.004). When compared with the sufficient group (25(OH)D ${\geq}30ng/mL$), the severe deficient group (25(OH)D <10 ng/mL) had 1.46 (95% CI 1.11-1.94) odds ratio for the risk of diabetes mellitus. This association was markedly strong in men and adults aged ${\geq}40$, whereas no significant association was observed in women and adults aged <40. Conclusions: We found that vitamin D deficiency may be associated with an increased risk for diabetes mellitus in Korean adults. Our findings suggest that intake of higher vitamin D may help reduce the risk of diabetes mellitus.

• Clinical and Experimental Pediatrics
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• v.54 no.7
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• pp.282-286
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• 2011

Breastfeeding is the best source of nutrition for every infant, and exclusive breastfeeding for 6 months is usually optimal in the common clinical situation. However, inappropriate complementary feeding could lead to a nutrient-deficient status, such as iron deficiency anemia, vitamin D deficiency, and growth faltering. The recent epidemic outbreak of obesity in Korean children emphasizes the need for us to control children's daily sedentary life style and their intakes of high caloric foods in order to prevent obesity. Recent assessment of breastfeeding in Korea has shown that the rate is between 63% and 89%; thus, up-to-dated evidence-based nutritional management of breastfeeding infants to prevent common nutrient deficiencies or excesses should be taught to all clinicians and health care providers.

• Journal of Preventive Medicine and Public Health
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• v.50 no.4
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• pp.278-281
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• 2017

Since 2006, type 1 diabetes in Finland has plateaued and then decreased after the authorities' decision to fortify dietary milk products with cholecalciferol. The role of vitamin D in innate and adaptive immunity is critical. A statistical error in the estimation of the recommended dietary allowance (RDA) for vitamin D was recently discovered; in a correct analysis of the data used by the Institute of Medicine, it was found that 8895 IU/d was needed for 97.5% of individuals to achieve values ${\geq}50nmol/L$. Another study confirmed that 6201 IU/d was needed to achieve 75 nmol/L and 9122 IU/d was needed to reach 100 nmol/L. The largest meta-analysis ever conducted of studies published between 1966 and 2013 showed that 25-hydroxyvitamin D levels <75 nmol/L may be too low for safety and associated with higher all-cause mortality, demolishing the previously presumed U-shape curve of mortality associated with vitamin D levels. Since all-disease mortality is reduced to 1.0 with serum vitamin D levels ${\geq}100nmol/L$, we call public health authorities to consider designating as the RDA at least three-fourths of the levels proposed by the Endocrine Society Expert Committee as safe upper tolerable daily intake doses. This could lead to a recommendation of 1000 IU for children <1 year on enriched formula and 1500 IU for breastfed children older than 6 months, 3000 IU for children >1 year of age, and around 8000 IU for young adults and thereafter. Actions are urgently needed to protect the global population from vitamin D deficiency.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• v.24 no.4
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• pp.403-412
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• 2021

Purpose: This study aimed to determine the serum 25-hydroxy-vitamin D (25(OH)D) status of breastfed infants less than six months old and their mothers, and factors affecting the status. Methods: This cross-sectional study was done on breastfed, term, Filipino infants less than six months old who were seen at local health centers and clinics in an urban area. The serum 25(OH)D levels of these infants and their mothers were determined, and their demographic data, nutritional status, sun exposure behavior, and maternal vitamin D intake were analyzed for correlation using regression models. Results: Among the 131 infants, 101 (77%) had vitamin D deficiency (VDD), which was defined as having 25(OH)D levels <37.5 nmol/L, and 13 (10%) had vitamin D insufficiency (VDI), with levels >37.5-50 nmol/L. Conversely, maternal VDD with levels <50 nmol/L was seen in 31 (24%) mothers and maternal VDI with levels 50-75 nmol/L, in 63 (48%) mothers. Infant age and maternal 25(OH)D status were independent predictors of infant VDD. Infants less than three months old were found to have a six-time increased risk of infant VDD (p=0.004). Infants who had mothers with VDD had a six-time increased risk, whereas those with maternal VDI had a four-time increased risk of infant VDD (p=0.049 and p=0.020, respectively). Conclusion: Both infant and maternal VDD and VDI were seen to be highly prevalent in this tropical, urban community. Young infants and maternal VDD/VDI independently increased the risk of infant VDD, whereas lack of sun exposure of the mothers increased the risk for maternal VDI.

• Korean Journal of Exercise Nutrition
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• v.25 no.2
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• pp.20-25
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• 2021

[Purpose] The aim of this review was to discuss the effects of vitamin D on physical performance and musculoskeletal injuries in athletes and provide information on the field applications of vitamin D. [Methods] A systematic review was conducted to identify studies on vitamin D in athletes that assessed serum vitamin D levels, vitamin D and physical performance, vitamin D and musculoskeletal injuries, and practical guidelines for supplementation of vitamin D. [Results] Several studies reported that a high proportion of athletes had vitamin D insufficiency or deficiency. Low serum levels of vitamin D in athletes were more pronounced in winter than in other seasons, and indoor athletes had lower serum vitamin D levels than outdoor athletes. Low vitamin D levels have been demonstrated to have negative effects on muscle strength, power, and endurance; increase stress fractures and other musculoskeletal injuries; and affect acute muscle injuries and inflammation following high-intensity exercises. Therefore, periodic assessment and monitoring of vitamin D levels are necessary in athletes; the recommended serum level of 25(OH)D is > 32 ng/mL and the preferred level is > 40 ng/mL (-1). In those with low levels of vitamin D, exposure to sunlight and an improved diet or supplements may be helpful. Particularly, 2000-6000 IU of supplemental vitamin D3 can be consumed daily. [Conclusion] Vitamin D is a potential nutritional factor that can significantly affect physical performance and musculoskeletal injuries in athletes. The importance and role of vitamin D in athletes should be emphasized, and the current levels of vitamin D should be assessed. Therefore, it is essential to periodically evaluate and monitor serum vitamin D levels in athletes.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.30 no.3
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• pp.321-330
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• 2020

Objectives: The purpose of this study was to compare vitamin D levels, sleep quality, and anxiety symptoms between shift workers and daytime workers and analyze the mediating effect of vitamin D and sleep quality between shift work and anxiety symptoms. Methods: The subjects of the study were 6744 people who received a medical examination while working for an electronics manufacturing company in 2016. We evaluated their shift work, vitamin D levels, sleep quality, and anxiety symptoms with blood samples and questionnaires. Chi-square test, t-test and path statistical analysis were performed. Results: The shift workers had significantly higher symptoms of anxiety than the day workers, significantly lower levels of vitamin D in the blood, and significantly poorer quality of sleep. The results of the pathway analysis confirmed that blood vitamin D and sleep quality had a mediating effect between shift work and anxiety symptoms. Conclusions: Shift workers should be constantly paying attention to mental health effects such as anxiety symptoms. Shift workers should also be alerted of the risk of vitamin D deficiency, encouraged about sun exposure and vitamin D intake, and required to undergo training and counseling on sleep hygiene.

• Journal of Nutrition and Health
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• v.46 no.6
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• pp.540-551
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• 2013

Vitamin D deficiency (VDD) is becoming an epidemic and thereby a global health problem. Further, VDD adversely affects calcium metabolism and skeletal health, and is associated with increased risk of several diseases, e.g., autoimmune diseases, several types of cancers, type 2 diabetes mellitus, cardiovascular diseases, infectious diseases, asthma, psoriatic arthritis, and etc. To evaluate the prevalence of VDD in Korea, and then to evaluate the association of several factors with serum 25(OH)D level, the author analyzed the data of 14,456 individuals who were 10 years of age and over from the Fifth Korea National Health and Nutrition Examination Survey 1 & 2 (KNHANES V-1 & 2) conducted by the Korean Centers for Disease Control & Prevention. As a result, among Koreans (age $${\geq_-}$$ 10years), 65.9% of males and 77.7% of females were below optimum blood serum 25(OH)D (20 ng/mL). VDD is more severe in female than in male at all age groups. In addition, the younger generations had less 25(OH)D level than older generations in Korea. The analysis by complex sample general linear model (CSGLM) suggested that blood 25(OH)D concentration was related with gender (p < .001), residence (p = .030), occupation (p < .001), anemia (p < .001) and physical activity (p < .001). In conclusion, VDD is pandemic and it is more severe in younger generations in Korea. Further, from the results by CSGLM, serum 25(OH)D status is closely related with the life style of Koreans.

• Journal of Periodontal and Implant Science
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• v.50 no.6
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• pp.368-378
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• 2020

Purpose: Vitamin D deficiency may cause bone loss and increased inflammation, which are well-known symptoms of periodontal disease. This study investigated whether serum 25-hydroxyvitamin D (25(OH)D) levels are associated with periodontal disease status and tooth loss. Methods: Cross-sectional data from 5,405 individuals aged ≥50 years (2,253 males and 3,152 females) were obtained from the 2008-2010 Dong-gu study, a prospective cohort study of risk factors for chronic diseases. Periodontal examinations were conducted to evaluate the number of remaining teeth, the periodontal probing depth (PPD), the clinical attachment level (CAL), and bleeding on probing. The percentages of sites with PPD ≥4 mm and CAL ≥4 mm were recorded for each participant. The severity of periodontitis was classified using the Centers for Disease Control and Prevention and the American Academy of Periodontology case definitions. Serum 25(OH)D levels were classified as reflecting severe deficiency, deficiency, insufficiency, or sufficiency. Multivariate linear regression analysis was performed to assess the associations of serum 25(OH)D levels with periodontal parameters and the number of remaining teeth after adjusting for confounders including age, smoking status, alcohol consumption status, month of blood collection, and physical activity. Multivariate logistic regression was used to evaluate the association between serum vitamin D levels and severe periodontitis. An overall statistical analysis and a stratified analysis by sex were performed. Results: Overall, the rates of severe deficiency, deficiency, insufficiency, and sufficiency were 6.5%, 67.9%, 22.4%, and 3.2%, respectively. After adjustment for confounders, vitamin D levels were directly associated with the number of remaining teeth, an association that was significant in males, but not in females. Sufficient serum 25(OH)D was associated with a low frequency of severe periodontitis. Conclusions: This population-based cross-sectional study indicates that low serum 25(OH) D is significantly associated with tooth loss and severe periodontitis in Koreans aged 50 years and older.

• Clinical and Experimental Pediatrics
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• v.60 no.7
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• pp.216-220
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• 2017

Purpose: Vitamin D is associated with various pathological conditions such as cardiovascular diseases and cancer. We investigated the relationship between vitamin D and Kawasaki disease (KD). Methods: We performed a retrospective review of the medical records of patients with KD between February 2013 and March 2016 in Daegu Fatima Hospital. Study participants were grouped according to vitamin D serum concentration. Group 1 included patients with 25(OH)-vitamin D ${\geq}20ng/mL$. Group 2 included patients with 25(OH)-vitamin D <20 ng/mL. We analyzed the clinical characteristics and laboratory data of the 2 groups. Results: Of the 91 patients, 52 were included in group 1, and 39 in group 2. Group 1 patients had significantly higher levels of calcium, phosphate, albumin and sodium than group 2 patients did. There were no differences in clinical characteristics, but the proportion of patients with polymorphic rash was significantly higher in group 2. Resistance to intravenous immunoglobulin was more frequent in group 2 (P=0.023). No significant difference in the incidence of coronary artery complications was observed. Conclusion: Low vitamin D levels are associated with resistance to intravenous immunoglobulin therapy in KD. Vitamin D deficiency might be a risk factor for immunoglobulin resistance in KD.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• v.13 no.2
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• pp.164-171
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• 2010

Purpose: Iron deficiency anemia (IDA) is one of the most common nutritional problems, despite a recent improvement of nutritional status of infants and children. We assessed the risk factors for IDA in infants and vitamin D deficiency and IDA by nutrition analysis. Methods: We analyzed blood tests and evaluated 103 children with IDA and 123 children without IDA, 6-36 months of age, who were cared for in our hospital between March 2006 and July 2010. Nutritional analysis using Canpro was performed among breastfed infants 6~12 months of age who had been diagnosed with IDA and had detailed diet histories. Results: Breastfed infants accounted for 87.4% and 40.7% of the IDA and comparison groups, respectively. The IDA and comparison groups began weaning food at 6.4${\pm}$1.8 and 5.9${\pm}$1.3 months, respectively. In the IDA and comparison groups, 46.4% and 53.5% began to adapt to weaning food within 4 weeks, respectively. The most common reason for hospital care of the IDA group was respiratory symptoms constituting 36.2%. Only 18.6% visited the hospital for palloror anemia. The Canpro analysis, performed on 11 infants with IDA, showed that iron and vitamin D were <40% and 30% of recommended intakes, respectively. Conclusion: Weaning food should be started 4~6 months of age in breastfed infants. In infants at high risk for IDA and vitamin D deficiency, screening tests should be recommended. The high-risk infants may require iron, vitamin D fortified formula, or oral supplements.